This invention relates to securing movable mechanical work-pieces, and more particularly, to locking pins used to retain adjustable machine components in designated locations.
It is known, for example in agricultural machinery, to employ towed implements, such as tillage devices, row cleaners, or the like that have adjustable work positions. The implement typically includes a main vehicle portion, and a working portion having a vertical bracket provided with at least one row of vertically spaced apertures. The bracket is adjustable relative to the vehicle portion using a vertical row of spaced openings on the vehicle portion that correspond to the openings on the vertical bracket. Relative adjustment of the height of the working portion to the vehicle portion is achieved by inserting a locking pin through corresponding openings on the working portion and vehicle portion.
Conventional locking pins often employ a cotter pin or locking ring to retain the pin in position in the bracket, especially when the machinery is used in extreme work environments subject to significant vibrations and/or torque forces. A disadvantage of the cotter pin mechanism is that the cotter pin requires extra operator effort to remove and replace when machine adjustment is desired. Also, cotter pins are easily lost in the field.
To address the problems of cottered locking pins, a more advanced locking pin has been developed, which employs self-contained locking elements, preferably ball bearings. The bearings are urged radially outward from a periphery of the pin to prevent the pin from being dislodged from the bracket. An example of such a pin is manufactured by Pivot Point of Hustisford, Wis. This pin employs a spindle reciprocating within a tubular body. The spindle holds the bearings in the extended, locking position, and actuation of the spindle by a user moves the spindle to a release position, allowing the balls to retract, and permitting pin extraction. One disadvantage of the latter pin is that when used in dusty conditions, in some cases dirt accumulates in the spindle passage, impeding spindle movement, and making the pin difficult to extract from the bracket. Similar problems have been encountered when using such pins on components of motocross motorcycles when conditions are muddy or dusty.
Consequently, there remains a need in the art for a locking pin that functions quickly, without the need for a cotter pin, and more reliably in extreme work environments.